Anterior Communicating Artery Aneurysms: Nonmodifiable Morphological Parameters Associated With Rupture Risk

Abstract

Background and Purpose The aim of this study was to investigate the relationship between arterial morphological parameters and the rupture risk of anterior communicating artery (AComA) aneurysms. Methods A hospital database was retrospectively reviewed to identify patients with AComA aneurysms. Morphologic parameters were evaluated on the 3-dimensional computed tomography angiograms. The patients were divided into two groups as ruptured and unruptured. Patient age, sex, morphological parameters such as aneurysm height and weight, neck diameter, aspect ratio (AR), size ratio (SR), bifurcation angle, aneurysm shape, and diameters of the artery were statistically compared between two groups. Results Ninety-five AComA aneurysms were analyzed in this study (60 ruptured and 35 unruptured). The aneurysm neck size (p = .005) and the diameter of the A1 segment of the ipsilateral anterior cerebral artery (i-A1) were smaller in the ruptured group than in the unruptured group (p = .001), but AR (p = .001) was higher. The number of patients with irregular shape aneurysm were higher in the ruptured group (p = .006). There was no significant difference between the two groups in terms of age, sex, aneurysm height and weight, bifurcation angle, and SR. Univariate logistic regression analysis showed that i-A1 segment diameter (odds ratio [OR]: -2.070, confidence interval [CI]: 0.030-0.531, p = .005), aneurysm neck diameter (OR: -0.409, CI: 0.491-0.899, p = .008), irregular shape (OR: 1.197, CI: 1.382-7.929, p = .007), and AR (OR: 0.880, CI: 1.315-4.417, p = .004) were significantly correlated with ruptured status. Multivariate regression analysis demonstrated that aneurysm neck diameter (OR: -0.457, CI: 0.410-0.977, p = .039) was the only independent variable for rupture. Conclusion AComA aneurysm rupture is more likely to occur in aneurysms with smaller i-A1 segment diameter, smaller aneurysm neck diameter, irregular aneurysm shape, and higher AR. Aneurysm neck diameter may be a more important determinant for rupture prediction.